House Sparrows occur naturally across most of Europe and much of Asia. It has also followed humans all over the world and has been intentionally or accidentally introduced to most of the Americas, sub-Saharan Africa, New Zealand and Australia as well as urban areas in other parts of the world.

Throughout the nineteenth century, House Sparrows were common to abundant in all the major islands of the Bailiwick but changes in farming practices and building methods have led to the widespread decline of one of the most familiar birds in the islands.

During the 1800s House Sparrows were thought of as a pest and there was a bounty on the birds and their eggs. Smith writes that in 1827 the States spent £72 5s 8d for the destruction of birds and eggs at the rate of seven eighths of a penny for a bird and one seventh of a penny for each egg. They were a major agricultural pest and Smith describes how they created enormous damage by leaving the towns for the country and invading the wheat fields, much in the same way that quelea destroy crops in Africa today. Dobson calculated this would have resulted in the destruction of some 20,000 birds and eggs that year. The total island population of House Sparrows would have been much much higher.

The change from a farming system dominated by mixed cropping to one dominated by intensive grass production will have severely reduced the amount of food available to birds in the wider countryside. At the end of the 1900s very little cereal was grown on the island and was restricted to several barley fields in the south-west of the island. This loss of cereal production and consequent loss of seed-rich environments such as hay ricks and grain stores coupled with the loss of suitable nesting areas through barn conversions and improvement in roof design is probably the major reason that House Sparrows are now restricted to areas inhabited by man.

Despite the decline, House Sparrows are still a common resident in gardens, parks and around farmyards albeit in much reduced numbers. Although there is no quantitative evidence, birders have noticed that numbers of House Sparrows seem to have continued to drop throughout the 1980s and 1990s.